1. Field of the Invention
The present invention relates to an image forming apparatus utilizing the electrophotographic process and an image forming unit adapted for use therein, and more particularly to an image forming apparatus such as a copying machine, a printer or a facsimile and an image forming unit adapted for use in the image forming apparatus.
2. Related Background Art
In an electrophotographic image forming apparatus, the image is formed by transferring, onto a recording material, a toner image formed on a photosensitive drum as an image bearing member, and, in a color image forming apparatus, there has been employed a configuration of transferring toner images of different colors, formed sequentially on the photosensitive drum, superimposing the toner images on an intermediate transfer member and collectively transferring such color images onto the recording material. In such configuration, in order to facilitate replacement of the deteriorated photosensitive drum and the consumed materials, there is widely adopted a configuration in which these components are formed as a unit detachably mountable to the main body of the apparatus.
For example, in an apparatus disclosed in the Japanese Patent Application Laid-open No. 8-137181 (hereinafter referred to as a xe2x80x9cfirst conventional apparatusxe2x80x9d), a photosensitive member unit and an intermediate transfer member unit are respectively constructed as independent units, and the apparatus is so constructed that a large movable frame opens by rotation to the front side of the apparatus and that the photosensitive member unit and the intermediate transfer member unit are respectively inserted from above.
Above the intermediate transfer belt, there is provided the photosensitive member unit integrally containing the photosensitive drum and a waste toner containing box, whereby the waste toner on the photosensitive drum is scraped off by a cleaning blade and is collected in the waste toner containing box at the back. Also the waste toner on the intermediate transfer belt is scraped off by another cleaning blade, then conveyed by a conveying coil to a position under a first conveying pipe, and is in turn conveyed by a screw in the first conveying pipe to a position above the waste toner containing box. Thereafter it is conveyed by a conveying coil in a second conveying pipe and is finally collected in the waste toner containing box.
The connecting part of the second pipe and the waste toner containing box belonging to separate units can be disconnected so that a shutter is opened and closed on connecting and disconnecting in order to prevent leaking of the waste toner.
In another example of the conventional color image forming apparatus (hereinafter referred to as a xe2x80x9csecond conventional apparatusxe2x80x9d), as disclosed in the Japanese Patent Applications Laid-open Nos. 11-30944 and 10-177329, there is proposed a configuration in which a photosensitive belt, an intermediate transfer belt and a waste toner containing box are integrally included.
In the second conventional apparatus, the photosensitive belt and the waste toner containing box are provided under the intermediate transfer belt. Also, as in the first conventional apparatus, there is employed a configuration in which a large movable frame opens by rotation to the front side of the apparatus and that an image forming unit integrally including an intermediate transfer member, a photosensitive member and a waste toner containing box is inserted from above.
However, the conventional color forming apparatus described above is associated with the following drawbacks.
In the first conventional apparatus, the intermediate transfer member and the photosensitive member are formed as separate units, and the presence of such two units results in a larger number of steps in the replacing operation by the user. The usability is also deteriorated by the leakage of the waste toner from the connecting portion for the waste toner between the units and by the inserting and extracting operations required at the mounting and detaching of the units.
Also there is required a large aperture for mounting and detaching the image forming units of two kinds. For this reason, there is adopted a configuration in which the entire front face of the apparatus opens by rotation, and such configuration imposes heavy work on the user despite of the presence of a damper mechanism, requiring a large space and a high rigidity of the frame for the rotating mechanism and also requiring a high cost.
Also in the second conventional apparatus, the photosensitive belt, the intermediate transfer belt and the waste toner containing box are integrally constructed as an image forming unit, which can be replaced by the user upon reaching the end of a predetermined service life. However, the photosensitive belt and the intermediate transfer belt have to be replaced when either reaches the end of its service life, even if the other is still usable, whereby a burden of a higher cost is imposed on the user.
In consideration of the foregoing, an object of the present invention is to provide an image forming unit capable of improving the usability and an image forming apparatus utilizing such image forming unit.
Another object of the present invention is to provide an image forming unit capable of achieving compactization and cost reduction, and an image forming apparatus utilizing such image forming unit.
Still other objects of the present invention, and the features thereof, will become fully apparent from the following detailed description.